The requested article 'Daniel Sans' is not available inside this ZIM, it was not possible to retrieve it from en.wikipedia.org.
When the ZIM you are browsing was built, en.wikipedia.org server failed to give details about this article HTML in a timely manner.
The missing article was replaced by the placeholder page you are currently seeing.
Let's hope the issue will be solved on en.wikipedia.org server and our next version of this ZIM will contain this article.